1. Technical Field of the Invention
The present invention relates to an apparatus and a method for adding wet ash to cement that can, for instance, effectively use modified ash, which is obtained by removing unburned carbon from fly ash generated in coal thermal power plants or the like, and others by feeding them to cement mills.
2. Description of the Related Art
Fly ash generated at coal thermal power plants etc. has been utilized for raw materials for cement and artificial lightweight aggregates and an additive for concrete and so on. When the fly ash is utilized for an additive for concrete, since unburned carbon included in the fly ash absorbs air-entraining water-reducing admixture and the like, the workability of the concrete is lowered. In addition, when casting the concrete, harmfully, unburned carbons float, and a black-color portion is generated at a joint portion of the cast concrete. Further, a large quantity of unburned carbon in fry ash causes a problem of lowered quality of artificial lightweight aggregate.
Then, in order to remove unburned carbon from fly ash with high unburned carbon content and effectively use the fly ash, for example, in the first patent document, a method for removing unburned carbon included in fly ash is described. The method can considerably lower unburned carbon content by adding shearing force, before flotation process, to original fly ash slurry including unburned carbon, to which a collector added.
Patent document 1: Japanese Patent 3613471 gazette